[gtk/wip/otte/macos-werror: 15/16] CI: turn on -Werror for MacOS build

[Benjamin Otte <otte src gnome org>]

commit a0c7f7f7611687196e3d954c86310bd5efc9d8fa
Author: Benjamin Otte <otte redhat com>
Date:   Wed Nov 3 23:35:03 2021 +0100

    CI: turn on -Werror for MacOS build
    
    The build is error-free and we want to keep it that way.
    
    We'd also like to make Timm do real work instead of having to fix clang
    warnings all the time and this build is a clang build.

 .gitlab-ci.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6ee0dfc57f..b4c7c1d042 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -172,7 +172,8 @@ macos:
     - export PATH=/Users/gitlabrunner/Library/Python/3.7/bin:$PATH
     - export MESON_FORCE_BACKTRACE=1
   script:
-    - meson -Dx11-backend=false
+    - meson ${COMMON_MESON_FLAGS}
+            -Dx11-backend=false
             -Dbroadway-backend=true
             -Dmacos-backend=true
             -Dmedia-gstreamer=disabled